US2965332A

US2965332A - Automatic tension device

Info

Publication number: US2965332A
Application number: US698439A
Authority: US
Inventors: Winthrop L Perry
Original assignee: Abbott Machine Co Inc
Current assignee: Abbott Machine Co Inc
Priority date: 1957-11-25
Filing date: 1957-11-25
Publication date: 1960-12-20
Anticipated expiration: 1977-12-20

Description

Dec. 20, 1960 w. L. PERRY AUTOMATIC TENSION DEVICE 2 Sheets-Sheet 1 Filed Nov. 25, 1957 W. L. PERRY AUTOMATIC TENSION DEVICE Dec. 20, 1960 2 Sheets-Sheet 2 Filed Nov. 25, 1957 AUTOMATIC TENSION DEVICE Filed Nov. 25, 1957, Ser. No. 698,439

Claims. (Cl. 242-150) This invention relates to an automatic tension device in which the load which applies tension to the yarn is controlled by a yarn arm responsive to the yarn tension. It may be shown that in such a device certain benefits are obtainable through use of a high mechanical advantage in controlling the load. The present invention provides a device in which these benefits, from high mechanical advantage, are obtainable over a wide range of differing entering tensions, the device employing a large potential load which is largely believed in'an automatic manner, only that portion of the large potential load which is unrelieved being employed to apply tension, and this unrelieved portion being distributed to a considerable number of movable disks. In the opening of the successive disks by a knot, only approximately that portion of each disks potential load which is unrelieved opposes the opening of the disk. The device is so constructed that inertia effects opposing opening of the disks are reduced to a minimum.

' Other features of the invention involve a novel means of guiding the yarn through the tension device in proper relation to successive disks, and novel means for supporting the yarn against successive movable disks and for supporting the movable disks themselves.

Other advantages features of the invention will be apparent from this specification in which the invention is explained by a description of a preferred embodiment thereof.

In the accompanying drawings,

Fig. 1 is a plan view of the automatic tension device;

Fig. 2 is a fragmentary front elevation, partly in vertical section on the line 22 of Fig. 1;

Fig. 3 is a rear elevation;

Fig. 4 is mainly in elevation as viewed from the line 4-4 of Fig. l, and partly in vertical section taken through the axes of the third and fourth disks;

Fig. 5 is a detail, mainly in horizontal section on the axis of the yarn arm and weight lever;

Fig. 6 is a vertical section taken at the axis of one of the disks on a larger scale than preceding figures;

Fig. 7 is a vertical section taken on the line 77 of Fig. 6;

Fig. 8 is a vertical section similar to Fig. 6 showing a modified form of mounting for supporting an upper disk by a spring; and

Fig. 9 is a horizontal section taken on the line 9-9 of Fig. 8.

Before a description of the preferred construction of the tension device of this invention, there will be pointed out, in an approximate manner, certain factors and rela- 'tions involved in obtaining some of the objects of this invention in its preferred construction.

In considering a tension device it is convenient to refer to a coefiicient C which represents the ratio between the increase in tension added to the yarn and the amount of loading force applied to the movable disk (or disks) in adding this tension. Thus, if 2 grams force applied to the disk increases the yarn tension by 1 grain the 2,965,332 Patented Dec. 20, 1960 coefiicient C would be 0.5. The coefiicient C is not simply a coefiicient of friction, because this coefficient C allows for the fact that not all the force applied to the disk is in turn applied to the yarn. For instance the disk may be mounted in such manner and in such relation to the yarn that only two-thirds of the loading force is applied to the yarn. Nevertheless, the coefiicient C varies with the character of the yarn and it is desirable to construct the device in such manner that it will give nearly the same results even though this coefiicient varies considerably.

Any particular final or outgoing tension may be thought of, for purposes of approximate calculations, as consising of three parts.

The first part is the tension of the yarn entering the device and this may be called the incoming tension.

The second part is what might be called an inherent minimum addition, tension which it is found will be added by the device even if the disk or disks are ineffective. This inherent minimum addition may be accounted for largely by the fact that the yarn bends around the yarn arm and receives a snubbing tension therefrom. This inherent minimum addition will vary and will of course be greater with rough yarn than with smooth yarn, and will be greater when operating at high tensions than when operating at low tensions. When operating in the region of 50 g. this inherent minimum addition might for example be in the region of 8 g.

The third part may be considered to be the tension applied by loading.

The tension applied by loading is under control of the final outgoing tension which acts upon the yarn arm. The device comes into equilibrium with a final tension which balances these three parts.

The intended operation is to decrease the third part, the tension applied by loading, as the first part, incoming tension increases. However to do this the outgoing tension must increase and there will accordingly always be some increase in outgoing tension as the incoming tension rises. It is desired to keep this increase in outgoing tension within narrow limits.

Assuming that the load is to be applied by weight, it is useful to distinguish between such part of the load as may be relieved, and any part which is not relievable and which may be called dead weight. Dead weight may represent weight of a disk or disks, connecting linkage and other parts which because of the construction of the device always contribute to the pressure upon the yarn, and may vary considerably.

The mechanical advantage M with which the yarn arm acts to relieve the load has an influence upon the characteristics of the device and there are advantages in making the mechanical advantage large. With increasing mechanical advantage M, the load is also increased.

The following Tables I and II, asume devices in which there is an appreciable but small amount of dead weight (50 g.), the device of Table I having a relatively low mechanical advantage M of 10 and the device of Table II having a large mechanical advantage of 30.

It will be seen that Table II where the mechanical advantage is 30, shows a better regulation at the lower values of incoming tension than does Table I, where the mechanical advantage is 10. However for incoming tensions above 15.33, Table II shows no better regulation than Table I. Thus, the final tensions are the same in Tables I and II for an incoming tension of 20 g.

In Table II through this range of incoming tensions above 15.33 there is as great an increase in final tension as in incoming tension, resulting in exceeding the desired final tension when the incoming tension is as high as 20 grams. If a lower final tension than 50 grams were aimed for, and the total load available adjusted accordingly,

3 Table I there would be an even larger zone or range of incoming tensions'in which-the final tension would increase as much as did the incoming tension. The following Table III isbased upona desired'final tension of 40 grams and an inherent minimum addition of 6.4 grams (on the assumption that this latter will diminish proportionately with the desiredfinal tension). It will be seen from this Table III that at incoming tensions above 6.93 g., an increasein incoming tension is reflected in 'an equal increase in final tension.

. Inherent minimu dition 6. 4 6. 4 6. 4 6. 4 6. 4 Tension desired to be addedby load=(2) (3) (4) 31. 6 26. 67 26.6 23. 6 13. 6 6. Load re quired for desired tension= ()/(l) 63. 2 53.33 53. 2 47. 2 27. 2 7. Totalload available. 1,200 1,200 1, 200 1,200 1,200 8. Dead Weight 50 50 50 50 50 9. Relievable load n 1, 150 1,150 1,150 1,150 1, 150 10. Load counterbalanced by final tension (See' 13 below) (13) XM '1, 140. 9 1, 150 1,150 1,150 1,150 11. Net load applied 59.1 50 50 50 50 12. Tension applied byload- I ing 29. 55 25 25 25 25 13. Final) tension (3)+(4)+ It may be explained that in these tables, up to a point where all of the relievable load is relieved, the final'tension (item 13) is calculated by the following equation, involving other items of the table:

(13): ni y+m M1 [M=l0. Dead weight=50 g.]

1, Cn'fifinient 0,5 2. Approximate desiredteir 5 i l m 50 1 3. Incoming tension 2 7 10 12 4. Inherent minimum'addition 8 8 8 8 8 5. Tension desired to be added by load=(2) (3)(4) 40 35 32 30 32 10 6. Load required for 'desircd tension=(5)/(1) 80 70 64 50 44 7. Total load available 500 500 500 500 500 8. Deadweight 50 50 50 50 50 9. Relievable load 450 450 450- 450 450 10. Load counterbalanced by final tension (See 13-beloW)=(l-3) XM..-.L 433.3 441.6 446.6 450 450 15 11. Net ioad'applicdfinn u. 66.7 58.4 53.4 50 50 12. Tension applied by loading 33. 3 29. 2 26. 7 i 25 13. Final tension (3)+(4)+ 20 Table II '[M =30. Dead weight=50 g.]

1 Cneffinierit 0,5 2. Approximate desiredtension (grams) 50 3. Incoming tension 2 10 4. Inherent minimum 8 8 8 8 8 5. Tension 'desire'd e added by load=(2). g (3)-(4).. 40 32 26.67 26 22 '6.-Load required r sired tension= (5)](1) 80 64 53. 33 52 I 44 7. 1, 500 1, 500 1, 500 1, 500 "-8-. 50 50 50 50 9. Relievable load 1,450 1,450 1,450 1,450 1,450 10. Load counterbalanced by final tension (See 13 below) 13) M.- 1,425 1,440 1,450 1,450 1,450 3 n. Netload 1ea.... 75 so so so 50 5 12.-l.ensionappied-byload- V ing 37.5 30 25 2s 25 13. Final tension (3)+(4)+- At and beyondv the vpoint where all relievable load is re.

It may further be explainedthat where, in these tables, the final tension (item 13) is calculated to a fraction of a gram, the purpose of carrying the calculation to such a fine degree is not because ofany necessary importance of the fraction of a gram in the final tension, but is "in order that theother:items. which afedcpndent upon item 13 will be approximately consistent with the final tension as indicated by item 13. "It 'will'be apparent that the calculations as to final tension should only be regarded as approximate because they are based on an assumed coefiicient'C and an approximate figure for the inherent minimum addition of item 4.

Thus far only asinglecoefiicient C of 0.5 has been assumed. I-nactual practice, this coefiicient will not remain constant but will -var y for different yarns and may also vary somewhat for the same yarn. A lower coefiicient will yield lower outgoing tensions and a higher coeiiicient will yield higher outgoing tensions. It may be seen that when operating in the region in which the relievable load is not totaly relieved, a device having a large mechanical advantage is less sensitive to these changes in coefficient than is adevice having a small mechanical advantage.

The effect of a slightly increased coefficient'is shown in Tables Ia and Ila where his assumed that in the de-. vices of Tablesl and ll-thecoefiicient is -0.6 instead of 0.5.-

Tdble la.

[M=10. Dead weighte=50gtl l. Coefiicient" 0.6. 2. Approxi nate tlshedten- W 'sio'n (are. as) 50 3. lnco'ni 1g ten ion..- -2- 7 10 12 20 4. lilie'e'it minimum addltion 8' 8' 8. 8. $3 5. Tensim dcsi'ed to be added by load=(2) (3)(4).- 40 '35 32 30 22 6. Loading equired for de- I si ed te nsi )n= (5)/(1) 66. 7 '58. 3 53. 3 50 36.7 7. Total load available..." 500 500 500 500 500 8. Dead veiht 50 50 50 50 50 9. Relievable load "450 450 '450 450 450 10. Load c unterbalanced by-finaltensim(See13 below) (13) XM 442. 8 450 450 450 '450 g et load apnlied 57. 2 50 50 50 13 24. 32 30 30 '30 30 44.28 45 48 50 58 Table Ila [M =30. Dead weiglit=50 g.]

1. Coeiiicient 0.6 2. Approximate desiredten- 'sion'(grans) '50 3. Incoming tension 2 10 33 11 16 20 4. Inherent minimum ad dition 8 8 '8 8, 8 5. Tension desired'to be ad- L i ded by load=(2) v 3) 4 40 31. 67 31 '26 '22 6. Load required for desired tension= (5)](1)-.. 66. 7 52. 8 51. 7 43. 3 36. 7 7. Total load available 1, 500 1,500 1,500 1,500 1,500 8. Dead weight..- "50 '50 505 '50 50 9 1,450 1,450 1,450 -1, 450 1,450 10. Load ed' by final tension (See 13 below) (13) M 1, 436.7 1, 450 1,450. -1, 450 1, 450 11. Net load'appiied. 63.3 '50 50 50 '60 i2. Tension applied byl 1 I ing 37. 98 30 e 30 30 30 13. Fi'ial I l,

Table I shows that the device provides -a-'cornpensat1ng action for incoming tensions up to l2'-grams,-' whereas Table -Iashows that the device 1 provides -a compens atingaction for incoming tensions ranging only up to 7 grams.

Such increase in coefficient also reduces the zone in which a compensating action is obtained in the device of Table II having the large mechanical advantage. Table II shows a compensating action up to incoming tensions of 5 15.33 grams, whereas Table IIa shows a compensating action for incoming tensions only up to 10.33 grams.

It may be seen from these Tables I, II, Ia and Ho that in the portion of the scale in which a compensating action is not produced, a change in coefficient from 0.5 to 0.6 increases the outgoing tension by 5 grams. Thus, close regulation is not consistently obtainable anywhere in this region, because various coeflicients will be encountered in practice.

Thus while the regulation has been improved in the .iower range of incoming tension, by adopting the large mechanical advantage of 30 rather than the relatively :small mechanical advantage of 10, a corresponding improvement is not shown throughout the scale.

It is therefore a problem how to extend the range of incoming tensions for which the benefits of a large mechanical advantage are secured.

The present invention takes into account the fact that in order to cause a large mechanical advantage of the yarn arm to be effective to give good regulation at both the higher and lower values of incoming tension, the effect of dead weight or unrelievable weight should be reduced. Any substantial reduction of the efiect of dead weight in Tables I to III, In and IIa would have been helpful since it would have extended upward the region in which a true compensating action would be obtained. It would also have reduced the eifects of variation in coefficient. By reducing the dead weight sufiiciently, it is possible to avoid the condition shown in several columns of Tables I, II, III, Ia and IIa where the net load applied (item 11) .35 considerably exceeds the load required (item 6) and a true compensation is not obtained. If the dead weight is completely counteracted the range of incoming tension for which true compensation is secured can extend up to the desired final tension minus the inherent minimum addition, i.e. an incoming tension of 42 g. for the device of Table II.

Table IV diliers from Table II by having its total load relievable, and having no dead weight.

Table IV [M =30. Dead weight =0] 1. Coe'ficient 0.5 2. Approximate desiredtension (grams) 3. Incoming tension 2 10 15 16 20 4. Inherent minimum addition 8 8 8 8 8 5. Tension desired to be added by load=(2) (3) (4) 40 32 27 26 22 6. Load required for de sired tension= (SJ/(1)..- 80 64 54 52 44 7. Total load available-.. 1,500 1,500 1,500 1,500 1,500 8. Dead wei ht 0 0 0 0 0 0. Relievabie load 1, 500 1, 500 1, 500 1, 500 1, 500 10. Load counterbalanced by final tension (See 13bel0W)=(l3)XM 1,425 1,440 1,449.3 1,451.4 1,458.9 11. Net load applied 75 60 50. 7 48.6 41.1 12. Tension applied byloading 37. 5 30 25.35 24.3 20. 55 13. Final tension (3)+(4)+ It will be seen that, for incoming tensions up to and 65 tion persists for the higher incoming tensions of 16 and a 20 grams.

For the range of incoming tensions from 2 grams to 20 grams, there is a maximum variation in final tension of only 1.13 grams.

The following Table IVa, assuming a coefiicient of 0.6 instead of 0.5 for the device of Table IV, shows that L the device represented by Table IV is insensitive to V assesse a u variation in coeflicient. In Table No for the range of incoming tensions from 2 grams to 20 grams, there is a maximum variation in final tension of only 0.95 gram.

Table IVa [M=30. Dead weight=01 1. Coetficient 0.6 2. Approximate desired tension (grams 50 3. Incoming tension 2 10 15 20 4. Inherent minimum ad ti n 8 8 8 8 5. Tension desired to be added by load=(2)- (ID-(4) 40 32 27 22 6. Load required for desired tension= (5)/ (1) 66. 7 53. 3 4 36. 7 7. Total load available 1,500 1, 500 1,500 1,500 8. Dead weight..- 0 0 0 0 9. Relievable load 1,500 1,500 1,500 1, 500 10. Load counterbalanced by final tension (See 13 below)=(l3) XM 1, 436.7 1,449.3 1,457.4 1,405.2 11. Net load applied 63.3 50.7 42. 6 34. 8 12. Tension applied by loading 37.98 30. 42 25. 56 20.88 13. Final tension (3)+(4)+ It will be noticed that the total load of 1500 grams is equal to the approximate desired tension of 50 g. multiplied by the mechanical advantage of 30 of the yarn arm. This total load is such as would be totally relieved when the incoming tension added to the inherent minimum addition of 8 g. will equal 50 g., that is, when the incoming tension is 42 grams. This is a higher incoming tension than may be encountered in many cases. It may therefore be desirable to use a greater total load, such that the desired 50 grams final tension will be obtaine for some lower value of incoming tension.

The total available load appropriate to give a desired final tension for any particular incoming tension and inherent minimum addition may be calculated by ascertaining the load required for this desired tension (item 6 of Table IV) and adding to this load the product of the desired tension and the mechanical advantage. It may be seen from Table IV that to obtain a final tension of 50 g. when the incoming tension is 20 grams, the total load available should be 1500 plus 44 grams.

Table V represents a device having a mechanical advantage of 30 and no dead weight and a total available load of 1544 grams. This table shows how the regulation, over a wide range of incoming tensions, is scarcely affected when the coefiicient changes from 0.5 to 0.6.

When the mechanical advantage is high, as in Table IV, the final tension will be sufiiciently close to the desired tension if the total load available is simply made equal to the desired tension times the mechanical advantage of the yarn arm, as in Table IV.

The reduction or elimination of dead weight becomes increasingly important when the device, as in the preferred form of this invention, includes a considerable number of individual upper disks, interconnected by linkage and all controlled by the yarn arm.

The reduction or elimination of dead weight is best effected by providing the individual upper disks with individual springs adapted to sustain the weight of the upper disks, the plungers and the linkages and connections whose weight the yarn arm is ineifective to relieve, so that by means of the springs the yarn is relieved from the downward pressure occasioned by the weight of the disks, plungers and linkage.

It is not essential that the weight of these parts be entirely sustained by the springs, but it is desirable that the springs should be able to sustain this weight when and if the relievable weight is totally relieved by the action of the yarn arm.

The springs may be if desired even stiffer than would be necessary to sustain the weight of the dead weight parts, and no harm is done if these springs, in addition to sus- 1. Coefficient "0.5 2. Approximate desired tension (grams) 50 50 "3. comingtenslo 2 10 20 2 4. Inherent minimum addit1on.'..' 8 8 8 8 5. Tension desired to be 'added "by 'loa'd='(2)- j (3)(4) 40 '32 22 40 6. Load required for desirod'tension=(5)/(1) 80 64 i 44 66.7 7- TOtal load available 1, 544 1,544 1, 544 '1, 544 8. Dead weight... 0 0 9. Re1ievableload.-; 1, 544 1,544 1,544 1,544 10. Load counterbalanced by final tension (See 13 below) (13) XM- 1,466. 1 "l, 481. 1 1, 500 1,478. 4 5 11. Net loadappliedfn 77.9 62.9 44 65.6

12.Tenslon"a"pp1ied by'loading -1 38. 95 31. 45 50 39. 36 13. Final tension (3)+(4)+ taining this weight, also tosome extent oppose and nullify the downward force of the 'reliev'able weight.

For instance in Tables IV and V, where it is assumed that the value qf dead weight has been eiractly eliminated,

by calanlation or by trial, opp osing forceof grams 0 would need to be compe hsated for, "and the total load favailablewould be ZOgrams greater, in'or derto' apply the .sarne tensions. Eomin g"tensio ns,"asshown inYtli'ese I abl es Iv ;and V would thnyield the same'final tensions as Shown niltsa bls i. r 4 r r -Althgugh see ingg gdreg istion over a wide'rang'eof incoming tensions very desirable, and requires consideration of t he problem of dead weight and use of a suiliciently largei rne cha'riical advantage"M,'the matter of passageof knots must also be considered, v n The problem of: d o r unrelievable weighfaffecting the compensatingactlon is avoided in'the'type of tension deviceinwhich the pressure of the disks is regulated by yarn-controlled positively 'actir g connections which bear against the lowerisurfaces of the disks "and force them upward against a loading force applied to their upper surfaces; thus in the patent to I IeiZ'erNo. 2,629,561 each of two upper disks'is forced upw-ardfr'orn'b'elow by connections from;thelyarrr' arnrfso that thefweight of the disks cannot be considpred unrelievable. That construction,.

however, in my opinion does notaccomplish the present inventions object of offering the min i-mum resistance to dis-placement ofthe' disks by knots. That Construction involves making available a load, acting downwardly on the tops of the disks, somewhat in excess of the force,

needed to bring the yarn from condition of zero tension or at least rninimurn incoming tension up to the full tension at which it is desired the yarn shall leave the disks. Therefore, displacement of a disk by a knot is opposed by considerably more than the amount of force which the disk applies to the yarn under average running conditions when the potential load is considerably relieved. From the standpoint of avoiding break-age it would be much better if only the partially relieved load upon a disk opposed itslifting to admit a knot. This partially relieved load, in the device of the present application will, on the average, be much'less than the maximum load which is applied. only when the incoming tension is zero.

It mightlbe though thatin the device of the Heizer patent only the net orpa'rtially relieved load upon the disk would oppose lifting of the disk by a knot. However, further consideration willshow that the inertia of the yarrr arm and 'connections to the lower face of the disk I. 1. tsvs t. thes a sf e' Tspondinglio. t s

egr eejthat-the disk mnst respondwithin the "iractionof a "second in which a knot is p'r'yin tha 'di sk upw'ardly. Thus" in the device of the Heizer patent, the actual prying apart of the'disks is necessarily opposed by an increased load upon the upper disk, which increase will be considerable "in mostcases, representing increase up to the disks sh ai'e of the full potential load; g'reaterthan necessary for even a condition of zero incoming tension. In the device of the present application itis sought to avoid thistype of increase'in' load'and to keep the load, at'the moment-of prying apart of the'disks, substantially no greater than the partially relieved value/which thedevice has been mai The accomplishment of this involves use of the; yarn arm to relieve-aweightwhich is used as a loadyand pro- 'vision of a system of linkage to distribute the unrelieved portion of the loadto a considerable number of movable "disks.

The tension device of this invention is shown "as mounted on a horizontal plate or platform 21 having a vertical flange 21 the plate or platform 21 being-adapted to be a part of the head of an automatic winding unit, not shown. 7

Yarn Y enters the device through a suitable yarn guide or pigtail 23 mounted'on the plate 21'and leaves the device through a guide or pigtail 24 carried at the end of a yarn arm 25, passing thence downwardly to the winding unit. Ann 25 is aflixed to a sleeve 26 which pivots freely on the reduced end portion of a shaft 2.7 rotatable in a bushing 28 in flange 21a, Fig. 5.

It is desired to make the passage of knots very easy, and to this end a considerable number of easily lifted upper disks 30 are employed, preferably siX as shown.

Each disk is rotatable about a'central plunger 31which is verticallyslidable in a sleeve 32 fast in theplate 21.

The several disks 30 are preferably located in an arc and the yarn Y is directed by the pigtail 23 and by small vertical guide posts 34 and by the pigtail 24 in courses which traverse the successive disks as chords of the disks circular perimeters, each at about one-half of the radius of the disk from its center. Underlying the course of the yarn beneath each disk a yarn supporting platform 35 of polished'rnetal provides a'srnooth path for the yarn in contact with the disk. Opposite to the yarn supporting platform 35, each disk is supported by a pin or button 36, also of smooth polished metal, supported from the plate 21. The undersurface of the rotatable disk, beipg "largely: "exposed; in'th'e sense of being largelybutf bf cohtacit with'any other part, the rotation of the disk readily jsw'eiepsdust or fly off fromthe yarn supporting platform,

., et f rce pr p v e a hewak e t I linkage "comprises" an initial linkj'40fiFig'. 4, 10 which.

d is applied "at"; s (center: rhed twosecondary links 4rand'42- onto eac 0 which games the initial link 4i) is hooked, and

spring wires

43, 44

and 45.

Spriiig wires

43 and 45 pass through holes in upturned ends of the respective

secondary links

41 and 42. Spring wire 44 extends through similar holes in the adjacent upturned ends of both

links

41 and 42. The end portions of

spring wires

43, 44 and 45 pass through holes in the plungers 31 and can apply downward force thereto. Thus there is an individually springy connection, comprising one end portion of a

spring wire

43, 44 or 45 between each plunger and the remainder of the linkage. The points of engagement of the initial link 40 with the

secondary links

41 and 42 are such that each plunger 31 is equally loaded.

The individually springy connections with the plungers of the disks permit the disks to be lifted easily and quickly by passing knots without having to overcome the inertia of the initial and secondary links or of the rather massive adjustable weight employed in the device, the means for transmitting force from this weight to link 40, and other movable parts such as the yarn arm.

The means for applying net force to link 40 includes a lever 50 which is held fast to the shaft 27 by a locking nut 51, Fig. 5.

A weight 52 is held by a hook 53 in any one of several holes in the lever so as to provide an adjustable amount of torque force at the shaft 27.

Shaft 27 carries a lever 55, Fig. 2, which bears against an adjusting screw 56 in a lever 57 fast on a shaft 58 which rotates in arms 60 extending from the under sur- :face of plate 21. Shaft 58 has an offset crank portion 58a which bears in a valley or pocket in the middle of the initial link 40 to apply a downward force thereto. By adjusting the position, or if desired the size, of weight 52 a potential force (corresponding to the relievable load previously referred to) of adjustable amount can be provided at crank 58a and the middle of the initial link 40. In running, a large part of this potential force is relieved and offset by the action of the yarn arm 25 so that only the necessary net force is applied to initial link 40 for distribution to the several movable disks.

It should be noted that this potential force will usually be so large that when this potential force is not largely relieved the

springs

43, 44 and 45 would be considerably distorted. However, when the yarn arm 25 is not acting to relieve this potential force, the weight arm 50 drops until it encounters a stop bracket 61, Fig. 3, whereupon the

springs

43, 44 and 45 are no further distorted. It will be understood that these springs are light in order to permit easy lifting of the individual disks by passing knots.

The relief of potential force by the action of the yarn arm is accomplished by the yarn arm 25 bearing downwardly upon a bent forward end portion 50a of the weight arm 50. It will be seen from the length of the yarn arm 25 and the effective lengths of

levers

55 and 57 and crank 58:: that the mechanical advantage of the yarn arm (at its pigtail 24) with reference to the point of application of force by the crank 58a is large, being in the construction shown 38.85. Therefore whether the load is determined by calculation and the weight 52 adjusted to provide this load at the crank 58a and middle of link 40 or the weight 52 is simply adjusted according to experience to yield the desired outgoing tension, the device will give a close compensation by virtue of the high mechanical advantage.

To obtain this colse and consistent compensation for the relatively higher values of incoming tension (that is, relatively high with respect to the desired outgoing tension) the dead weight which is unrelievable by the yarn should be reduced or eliminated. In the device of this application, this problem of dead weight is increased over any problem of dead weight in any ordinary tension device because of the presence of the system of distributing linkage of which the weight cannot be relieved by the yarn and, as well as by the presence of the consider able number of plungers and disks.

In the device as shown in Fig. 6 a light compression spring 65 is interposed between each upper disk 30'and screw 56 without pressure upon the yarn on the yarn supporting platforms 35, thereby eliminating the factor of dead weight. As indicated above, no difficulty is encountered if the springs 65 are a little stiffer than re quired for merely relieving the dead weight, in which case a slightly greater load should be made available at the crank 58:: and middle of initial link 40. The springs 65 are not interfered with by the yarn, or vice versa, because the guide pins 34 hold the yarn well away from the springs. The section line 7-7 in Fig. 6 passes.

through the line of travel of the yarn.

There are certain advantages in employing flat springs: instead of the coil springs 65. Figs. 8 and 9 show a. construction in which the yarn is supported by a lower' disk 66 which is loosely centered about the sleeve 32 by' a locating washer 67 of dished shape. A generally flat: spring 70 is supported at its ends by the washer 67 and v is loosely centered by the sleeve 32. A little tubular element 71, also loose on the sleeve 3.2, is interposed between the lower surface of upper disk 30 and the spring 70. The effect of this construction is to sustain the weight of the parts that would otherwise have a dead weight effect. In Fig. 8 the spring 70 is shown as slightly deflected by its share of the weight of these parts.

The system of linkage and associated parts of the tension device are particularly intended to avoid back,- lash or lost motion such as would cause loss of control of the tension or cause hunting. First, it will be apparent from the drawings that the effect of the weight of the various parts of the linkage is always such as to stress the elements of the linkage in a manner tending to apply downward force to the disks. Also, it may be seen that whatever force is applied to the linkage under control of the yarn arm is also such as to stress the elements of the linkage in a manner tending to apply downward force to the disks. For example, the lever 55, Fig. 2, is never called upon to force lever 57 upwardly and crank 58a is never called on to force link 40 upwardly, and in fact lever and crank 58a can only exert downward force. Thus the linkage may be said to be free of reversals of stress during operation, and this feature eliminates backlash and lost motion. The springs or nevertheless prevent the weight of the linkage parts from constituting an uncontrolled or unrelievable dead weight load upon the disks.

The movement of the weight arm 50 damped by a dashpot indicated at 80.

It may be noted that in the construction shown the weight arm 50, without any weight 52, would exert some torque on the shaft 27 and hence provide some load at the crank 58a. It may in some cases be desirable to more or less balance the movable parts (minus the weight 52) around the axis of shaft 27, so that the torque effect is preferably of the weight of the parts other than the weight 52 is eliminated or reduced and a more nearly direct relation secured between the position of the weight 52 and the load made available. For this purpose there may be provided a counterbalancing weight 52a adjustably positioned on the weight arm 50.

By way of example, it may be assumed that the weight or weights are adjusted, either by means of calculation or by trial and error, so that a load of 2006.5 grams is available at the middle of initial link 40. The figure of 2006.5 grams may he arrived at by multiplying the desired tension 50 grams) by the mechanical advantage (38.85), making a product of 1942.5 grams, and adding to this latter the item of 64 grams. This adjustment corresponds knots without breakage.

rsess enrich*withaa imsommgeasier!"erinsists The final tension ofapprokimately so'igr'amsgaetmg leaving only approximately "64 grams net" or llnrelieved load, to be divided among'thesiX disks'and applied there- "to by the springy' connections.

n will 'be uridrstood that the aboveadju'stmentand condition of operatidn"arereferred to only by wa fof *explanation' of the invention, and that these maybevaried widely. V

'Also, no attempt is" made to set forth theactriakweights of parts of this device which wouldcontr'ibiite tothedead "weight (were'this de'ad Weight not counteractedby the springs 65- m7 0) because the" weights of these'parts will naturally vary with their sizes, "which in 'turn' 'will vary with the specific design'ofthe device.

I claim: I

1. An automatietension device cor'npri'singa plurality of tension disks, means for supportingthe' yarn against to the several disks-loading means- "for"applying saidforce "to the linkage, a yarn ar'rn 'ur'ge'd' by the tension of the running yarnto relieve the force of the loading-"means "applied to the linkage; the device including a connectio'n between the yarn" arm and the loading mans for pre- *mit'tingthe yarn arm to relievesaid'for'ce, wherebyme 'n'et load comprised of the force' afiorded 'by 'theleading' means as relieved by the force afiorded'by the 'ya'r-n arm is distributed' to the several disks, said linkage-* ineluding individually springy connections to the individual disks, each said springy connection-to a disk'receiving its distributive share of said net load and being yieldable to permit its corresponding disk to lift to admit'a knot.

2. An-automatic'tension' device comprising 'afplurality of tension disks, meansfor supporting the yarn against said'disksya linkage suspended from the several disks,

"said linkage having a-point'at which downward forceis applied thereto and distributing said force from sa'id point to the several disks, a weight connected'to the linkage to" exert the said force upon the linkage, a"yarn"arm urged by the tension of the running yarn to'relieve the force of said weight applied to the linkage, the device/ including a connection between the yarn arm and the weight for permitting the yarn'arm to relieve'said'fo'rce, whereby the netload comprised of the forceafi'orded by the-'wei'ght as relieved'by the force afforded bythelyarn ar m- 'is distributed to the'several disks, said linkage'including individually springy-connectionsto the individual'disks,

each said 'spr'ingy connection to a disk receiving its distributive share of said net load and being yieldable' to permit itscorrespondingdiskto lift to admit alarm.

p 3. AEa'HtOinatIc" sionde'vice comprising aph'irality :"of *ter'isionidis'k's, ans "fdfsuppo'rting the yarn' "against *said disks, 'plu' s for "pulling the disks "down "against the "supporting nsfa linkage -suspended "from the "several plli'n'ge'rs, said linkage'having aipo'int atwhich idownwardior'ceis"applied theretoand distributing said 'fo'rcetro'rn said point to the several'plungers, a'weight connected"tothe' linkage to exert the saidforce'on the 'linkage,a yarn arm urged b'ythe tension'of the running yarn' to 'relievethe' force of said "weight "applied to the linkage, the device including a connection betweenthe yarn arm and" the weightfor permitting'thelyarn arm to relieve said force, wherebythe'net load comprised of "theforceafford'ed'by theweight as relieved by the force *a'fiordedbythe yarn'arrn is distributed to the several,

disks, said linkage including an' initial yoke receiving said net load, secondary yokes each'receiving a share of saidnet load from the'initial yoke, and springy'connec- 'tions from" the secondaryyokes to the plungers,-each said springy connection to a'plunger'receiving its distributive share of said net loadandbeing 'yieldable'to permit its corresponding 'disc to lift" to admit a knot.

4. An automatic tension device comprising av plurality of tension-disks;meansfor supporting the yarn against said disks, plungers'adapted to pull the respective disks downwardly, s'prin'gy wire connections between pairs of said plungers, 'a system' of linkage suspended from the spring'y 'wire connections, said linkage having a point at which uownwar'd force is" applied thereto and distributing said force froni 's'aid point to the springy-wire connections, -awei'ght"connected toapply downward force to the linka'ge at "said point; a yarn arm responsive to the tension of the "yarn'and-connectedto the'weight so as to relieve the aewnwardrorce 'applidby'the weight thus varying the netdownward' force appliedto the linkage, wherebyeach said springy connect'ion receives its distributive share of said net downward force, so-that the springy connection to any-individuakplunger permits easy lifting of the corresponding upper" disk bya passing'knot.

5. A yarn tensiondevice comprising a plurality of upper disks, "supports for the yarnbeneath said disks, plungers for pulling the upper disks down against the running yarn'on-the supports, a system of linkage interconnecting'said plungers, loading means for applying a downward force tosaid linkage,the linkage distributing said force tothe'plungers, a yarn arm responsiveto the yarn'ten'sion and c'onnectedto said loading means for relieving 'said forcef-said linkage including individual springy connections to the'several plungers, such springy connections each receiving its distributive share of'the net downward force applied to the linkage as a whole, and individual springs associated with the individual upper disks and tending to relieve the yarn from downwardpr'e'ssu're occasioned by weight of the disks, plungers and linkage 'wh'en'said yarn arm relieves said "downward force.

" References" Cited in'the file of this patent UNITED STATES PATENTS Pigeon has. Nov. 14, 1922